Over the years the sizes of barrels for electroplating apparatus have been standardized such that the barrels are interchangeable as between manufacturers. Similarly all such barrels are designed to be symmetrical about the axis of rotation. It is common in the trade to refer to a "16 inch barrel" and those in the trade will know that the individual has referred to a barrel of plastic construction which is symmetrical having six sides with one removable side used as a door for filling and emptying the barrel and where the dimension diagonally across between parallel sides is approximately 16 inches; the five side panels (exclusive of the removable door) will be permanently affixed to two end pieces having a generally circular periphery but with perhaps two flat areas, one being parallel with and adjacent to the door opening and the other being parallel with and remote from the door opening.
Where heavy loads are to be tumbled in the barrel it is conventional to have heavily reinforced bars at the corners of the panels because this is thought to be the most likely area of failure. As a general rule both the barrel and the reinforcing bars are of polypropylene or the like. An example of conventional corner reinforcement is noted in that 1969 patent to Kirkpatrick et al., U.S. Pat. No. 3,442,783.
Conventionally, the polypropylene end pieces of the barrel are grooved and the five permanently affixed side panels are mounted in the grooves, either be welding and/or bolting.
The reason for standardized sizes of electroplating barrels is that electroplating tanks must be standardized to receive such barrels and to receive standardized anode baskets which hold the copper, zinc, etc., balls or pieces which comprise the metal which is being plated on the contents of the electroplating barrel. Obviously, it would be desirable to increase the volume of the barrel without increasing its radius of rotation because that would increase the amount of material that could be plated in a unit of time in a conventional electroplating tank.
During the course of research on ways to increase the volume of the electroplating barrel without resorting to anything other than conventional standardized sizes of apparatus currently available, the inventor herein discovered the dimensional relationships to be explained subsequently.